import tkinter as tk

def OnBtn():
    print("on click btn")

top = tk.Tk()
top.configure(bg='lightblue')
top.title('Hello Tk')
top.geometry('640x480+100+100')
top.resizable(True, False)
btn1 = tk.Button(top, text = 'btn1', command = OnBtn)
btn1.pack(fill=tk.X)
btn2 = tk.Button(top, text = 'btn2', command = OnBtn)
btn2.pack(fill=tk.X)
btn3 = tk.Button(top, text = 'btn3', command = OnBtn)
btn3.pack(fill=tk.X)
btn4 = tk.Button(top, text = 'btn4', command = OnBtn)
btn4.pack(side=tk.LEFT, fill=tk.Y)
btn5 = tk.Button(top, text = 'btn5', command = OnBtn)
btn5.pack(side=tk.LEFT, fill=tk.Y)
btn6 = tk.Button(top, text = 'btn6', command = OnBtn)
btn6.pack(side=tk.LEFT, fill=tk.Y)
btn7 = tk.Button(top, text = 'btn7', command = OnBtn)
btn7.pack(side=tk.TOP, fill=tk.X)
btn8 = tk.Button(top, text = 'btn8', command = OnBtn)
btn8.pack(side=tk.TOP, fill=tk.X)
btn9 = tk.Button(top, text = 'btn9', command = OnBtn)
btn9.pack(side=tk.TOP, fill=tk.X)
btn10 = tk.Button(top, text = 'btn10', command = OnBtn, bg='blue')
# btn10.pack(side=tk.TOP, fill=tk.BOTH, expand=tk.TRUE)
# btn10.pack(side=tk.LEFT, fill=tk.BOTH, expand=tk.TRUE)
btn10.pack(side=tk.LEFT, fill='both', expand='true')

top.mainloop()
